Problem enabling I2C3 in Wandboard Quad

raulina — Tue, 01 Aug 2017 12:58:41 GMT

Dear all,

I have a wandboard Quad rev B1 with ubuntu and kernel 4.9.35. I need to use 2 I2C different ports. I developed a code that works well in I2C2, but fails in I2C1. I remember having read many people saying that I2C1 is not properly working because of the hdmi CEC (which shouldn't affect me because I am not using a monitor), so I decided to enable I2C3 while I try to figure what is wrong with I2C1. I also want to enable spidev to get /dev/spidev0.0.

I must say I am a newbie in the world of embedded systems and device trees.

To do so, I firstly followed Robert's Nelson tutorial, and then I modified imx6q-wandboard-revb1.dts from the files I with the following code:

/* * Copyright 2013 Freescale Semiconductor, Inc. * * Author: Fabio Estevam <fabio.estevam@freescale.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ /dts-v1/; #include "imx6q.dtsi" #include "imx6qdl-wandboard-revb1.dtsi" / { model = "Wandboard i.MX6 Quad Board rev B1"; compatible = "wand,imx6q-wandboard", "fsl,imx6q"; memory { reg = <0x10000000 0x80000000>; }; }; &sata { status = "okay"; }; &ecspi1 { fsl,spi-num-chipselects = <1>; cs-gpios = <&gpio2 30 0>; /* EIM_EB2 */ pinctrl-names = "default"; pinctrl-0 = <&pinctrl_ecspi1>; status = "okay"; spidev@0 { compatible = "rohm,dh2228fv"; spi-max-frequency = <10000000>; reg = <0>; }; }; &i2c3 { clock-frequency = <100000>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_i2c3>; status = "okay"; }; &iomuxc { pinctrl-names = "default"; imx6q-wandboard-revb1 { pinctrl_ecspi1: ecspi1grp-1 { fsl,pins = < MX6QDL_PAD_EIM_D17__ECSPI1_MISO 0x100b1 MX6QDL_PAD_EIM_D18__ECSPI1_MOSI 0x100b1 MX6QDL_PAD_EIM_D16__ECSPI1_SCLK 0x100b1 MX6QDL_PAD_EIM_EB2__GPIO2_IO30 0x000f0b0 MX6QDL_PAD_KEY_COL2__GPIO4_IO10 0x000f0b0 >; }; pinctrl_i2c3: i2c3grp { fsl,pins = < MX6QDL_PAD_GPIO_5__I2C3_SCL 0x4001b8b1 MX6QDL_PAD_GPIO_16__I2C3_SDA 0x4001b8b1 >; }; }; };

Then I execute

make imx6q-wandboard-revb1.dtb

and I copy it to /boot/dtbs/4.9.35-armv7-x4/imx6q-wandboard-revb1.dtb

/dev/i2c-2 now appears, but always gives timeout when I try to write on it. With an oscilloscope I don't see any change in the voltage of the lines that theoretically are assigned to the pins I chose. Besides, Ethernet stops working. All this makes me thing I am using the wrong pins, but according to the page 17 on the schematics, I2C3 is wired to GPIO5 and GPIO16...

What am I doing wrong?

Thank you very much

topic Problem enabling I2C3 in Wandboard Quad in i.MX Processors

Problem enabling I2C3 in Wandboard Quad